Consumers have long preferred meats and other foods which are moist, flavorful, and tender. The meat processing industry has recognized that these characteristics may be improved by tumbling pieces of meat in a rotating tumbler in the presence of a marinade and under reduced pressure.
The application of a vacuum expands and removes the gases located in the interstitial spaces within the meat and assists in effecting the absorption of the marinade into the meat. The application of a vacuum also helps mechanically distort the meat by expanding it, which assists in the breakdown of the meat fibers to enhance tenderization. The marinade typically contains tenderizing agents, flavoring agents as well as moisture, and thus the absorption of the marinade into the meat further enhances the moisture content, the tenderization, and the flavoring of the meat. The increased moisture results in a moister cooked meat product. The principal purpose of physically tumbling the meat pieces is to cause the marinade to penetrate throughout the entire piece of meat as a result of the repeated compression of the meat resulting from impact with other meat pieces and the tumbler. Additionally, the mechanical action of tumbling further mechanically works the meat product to enhance tenderization.
In conventional vacuum tumbling, the interior walls of the tumbler are provided with a plurality of baffles which enhance the stirring action and lift the meat pieces above the axis of drum rotation so that they can fall down into the marinade and upon other meat pieces in order to enhance stirring and the physical beating of the meat. Typically, the meat is placed in such a rotatable drum with the marinade and a closure is sealed. A vacuum is then drawn, the vacuum pump is disconnected from communication with the drum, and the tumbling action is begun by driving the drum in rotation. As the drum contents are tumbled, the pressure slowly increases in the interior of the drum as a result of the escape of gases from the meat pieces and the vaporization of liquid contents within the drum. One common practice is to use industrial size tumblers which may hold on the order of 8,000 pounds of meat. Rotation is continued for a half hour time interval, followed by a time interval, such as a half hour, of no tumbling, which is termed the "rest period". Conventionally, the tumbling period and rest period are alternated typically for an eight hour period. By the time the tumbling is complete, the interior pressure has risen substantially over the eight hour period. The meat products are then removed and packaged or processed further.
The prior art technology has some disadvantageous characteristics which the present invention seeks to improve.
First, it is desirable that the pieces of meat, following treatment in the tumbler, exhibit an appearance and other physical characteristics which are as close as possible to those of the fresh meat product which were placed into the tumbler. Conventional tumbling processes often cause physical damage to meat products, cutting the meat of some products or placing cuts on the skin, sometimes causing the bones of bone-in meat product to be broken or torn away from the meat. It is theorized that this results from the fact that prior art tumblers are provided with baffles which lift the meat products above the axis of rotation so that they fall further down with a greater striking force, often repeatedly falling upon the relatively sharp edge of a baffle moving along the bottom of the rotating drum. The physical damage to the meat products is sometimes so extensive that processors must place the meat product in a former and apply pressure in an attempt to return it to the shape of the original piece. Sometimes, because of the likelihood of such physical destruction, moisture and marinade is instead added to a bone-in product by means of hypodermic injection instead of by tumbling.
It is therefore an object and feature of the present invention to improve the appearance and presentation of the meat pieces treated in a tumbler by reducing or eliminating the physical damage or alteration to the pieces of meat and to other less durable foods such as vegetables.
One purpose of tumbling is the uniform penetration of the entire piece of meat with a substantial quantity of marinade. A purpose and feature of the present invention is to substantially reduce the time which is required to accomplish at least the same amount of marinade pick-up and penetration as is accomplished in the prior art, but to do so in a substantially reduced time. For example, tests have shown that, using the present invention, as much or more pick-up and penetration can be accomplished with the present invention in a time period of four hours as conventional technology can accomplish in eight hours. One advantage of this is that the meat product is tumbled for a shorter period of time and thus is held at a higher temperature for a shorter period of time. This permits less time for bacterial action, thus reducing bacteria levels in the tumbled product, which in turn increases shelf life. Another advantage of the reduced time is that production throughput and efficiency are increased, consequently lowering the cost of processing.
A typical meat treating tumbling apparatus and method for use on a smaller scale is illustrated in U.S. Pat. No. 3,928,634.